1. Field of the Invention
The present invention generally relates to antenna devices.
2. Description of the Related Art
An antenna device whereby high capacity communications can be performed is used for, for example, Bluetooth (registered trademark) at 2.4 GHz band standardized as IEEE 802.15, wireless LAN (Local Area Network) at 2.4 GHz band standardized as IEEE 802.11b or IEEE 802.11g, wireless LAN (Local Area Network) at 5 GHz band standardized as IEEE 802.11a, or the like.
In addition, antenna devices having plural resonance frequencies, accompanied with diversification of service conditions or the like, have been suggested. See, for example, Japanese Laid-Open Patent Application Publication No. 2004-201278 and Japanese Laid-Open Patent Application Publication No. 2008-124617.
In the meantime, in the antenna devices having plural resonance frequencies, it is relatively difficult to make adjustments for achieving good characteristics at each of the resonance frequencies.